The constituents of the leaves and stems of Davesia latifolia / by Frederick Belding Power and Arthur Henry Salway.

  • Power, Frederick B. (Frederick Belding), 1853-1927
Date:
1914.]
Catalogue details

Licence: Public Domain Mark

Credit: The constituents of the leaves and stems of Davesia latifolia / by Frederick Belding Power and Arthur Henry Salway. Source: Wellcome Collection.

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    melted at 135—136°. This substance gave the colour reactions of the phytosterols, and evidently belonged to that class of compounds. 0-0844* gave 0'2594 C02 and 0‘0898 H20. C = 83'8; H = 11’8. C27H4G0 requires C = 83'9; H = 1T9 per cent. Examination of the Fatty Acids. The aqueous, alkaline liquid which had been extracted with ether for the removal of the unsaponifiable material, as above described, was acidified with dilute sulphuric acid, and again ex¬ tracted with ether. This ethereal extract was filtered to remove a quantity (5 grams) of indefinite resinous material, the liquid being then washed, dried, and the solvent removed. The residual fatty acids were then converted into their methyl esters by heating with methyl alcohol in the presence of dry hydrogen chloride. The product thus obtained was distilled under diminished pressure, and three fractions were collected, which boiled respectively at 100—160°, 160—200°, and 200—210°/15 mm. The first fraction, which amounted to about 7 grams, was found to consist largely of methyl benzoate. The middle fraction (b. p. 160—200°/15 mm.) was very small in amount, the larger proportion of the methyl esters being contained in the fraction distilling at 200—210°/15 mm. As this contained some unsaturated esters, it was hydrolysed, the fatty acids thus obtained converted into their lead salts, and the latter treated with ether. The portion soluble in ether, when decomposed by hydrochloric acid, yielded 5 grams of liquid acids, whilst the insoluble portion gave about 3 grams of solid acids. The Liquid Acids.—These acids, when distilled under diminished pressure, passed over between 225 and 235°/15 mm., the greater part distilling at 230—233°/15 mm. as a pale yellow oil. An analysis and a determination of the neutralisation and iodine values gave the following results : 0-0807 gave 0-2280 C02 and 0‘0835 H20. C = 77'l; H = 115. Neutralisation value —201; iodine valuer 1732. C18H32O2 requires C = 77T; H=11'4 per cent. N.Y. = 2004; I.V. = 181-4. It would appear from these results that the liquid acid consisted of nearly pure linolic acid. The Solid Acids.—These acids, when crystallised from alcohol, separated in glistening leaflets, melting at 57—58°. The material was analysed and its neutralisation value determined :